Statistical Study of Host Fish for the Round Pigtoe Mussel (Plueurobema coccineum)
By Meggie Marzec
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Introduction
• Mussels clean rivers and streams
• Indicate health of river system
• Round Pigtoe threatened in MN, native to St. Croix
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Introduction
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Introduction
Glochidia with and without tissue
Previous studies show there may be a difference
Photo taken by Dr. Miller
Previous Studies
• Spotfin shiner, common shiner and hornyhead chub are host fish
• Golden shiner and creek chub are marginal host fish– From 2003 Host Fish Suitability Trial
Previous StudiesFigure 1 - Number of Glochidia and Juveniles Produced Over
Time for Spotfin Shiner
0
2
4
6
8
10
12
14
0 5 10 15 20 25 30 35 40
Days after Glochidial Infestation
Number of Mussels
w/o tissue
w/ tissue
juveniles
•2003 Study, glochidia without and with tissue as life cycle stages
Goals
• Find which host fish is statistically stronger: hornyhead chub or common shiner
• Find new host fish
• Study glochidia without tissue and with tissue as life cycle stages
Procedure
• Collect host fish and mussels from St. Croix River
• Infest fish with glochidia and check siphonate every three days
• Fish in statistical study kept in individual aquaria
Results
hornyhead chub
total # of glochidia, juveniles
# of juveniles
% transformation
1 82 54 67% 3 101 59 58%
Average Percent Transformation for hornyhead chub 63%
spotfin shiner total # of glochidia,
juveniles # of
juveniles %
transformation 2 70 23 33% 3 47 20 43% 4 102 21 21% 5 59 2 3%
Average Percent Transformation for spotfin shiner 25%
Table 1: Percent Transformation for hornyhead chub and spotfin shiner
Results
Figure 2 - Number of Glochidia and Juveniles Produced Over Time for Common Shiner
0
20
40
60
80
100
120
0 5 10 15 20 25
Days After Glochidial Infestation
Number of Mussels
glochidia w/otissueglochidiaw/tissuejuveniles
ResultsFigure 3 - Number of Glochidia and Juveniles Produced
Over Time for Blackchin Shiner
0
2
4
6
8
10
12
14
0 5 10 15 20 25
Days After Glochidial Infestation
Number of Mussels
glochidia w/otissue
glochidia w/tissue
juveniles
ResultsFigure 4 - Number of Glochidia and Juveniles
Produced Over Time for Longnose Dace
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25
Days after Glochidial Infestation
Number of Mussels
glochidia w/otissueglochidia w/tissuejuveniles
ResultsFigure 5 - Number of Glochidia and Juveniles
Produced Over Time for the Mimic Shiner
0
1
2
3
4
5
6
7
8
9
0 5 10 15 20 25
Days After Glochidial Infestation
Number of Mussels
glochida w/otissueglochidiaw/tissuejuveniles
Conclusions
• Common shiner, mimic shiner, blackchin shiner and longnose dace are host fish
• Not able to determine difference between glochidia without tissue and with tissue
• It appears that related fish host the same mussel
Practical Applications
• Results of the statistically stronger host fish could be used to reintroduce the Round Pigtoe mussel by making raising mussels in a laboratory setting more efficient
• By finding that related fish host the same mussel, host suitability trials can be simplified
Future Studies
• Repeat the study with many species of fish from the same family
• Conduct a Histological study with pictures of mussels at different life cycle stages to deterimine if glochidia without and with tissue are separate life cyce stages
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